Drop-out fuse



Feb. 19415 T. F. JOHNSON DROP-OUT FUSE Filed April 24, 1939 2Sheets-Sheet l awe/WM 17F c o bvwr Feb. 4, 1941. JOHNSON 2,230,955

DROP-OUT FUSE Filed April 24, 1959 2 Sheets-Sheet 2 Patented Feb. 4,1941 PATENT OFFICE I DROP-OUT FUSE Tomlinson F. Johnson, Atlanta, Ga.

Application April 24, 1939, Serial No. 269,712

11 Claims.

This invention relates to drop-out fuses'for high tension transmissionlines and, among other objects, aims to provide a greatly improved fuseassembly of the general type shown in Patent No. 2,074,913 embodyingnovel means to support the fuse unit and cause it to drop out and swingto a substantially vertical position. Another aim is to provide in afuse assembly of this type a spring biased combination contact elementand bumper coacting with the lower end of the fuse unit and a springbiased contact arm carrying a flip-out element coacting with the upperfuse terminal.

Other aims and advantages of the invention will appear in thespecification, when considered in connection with the accompanyingdrawings, wherein:

Fig. 1 is a side elevation of a fuse assembly embodying the invention;

Fig. 2 is a front elevation; I

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1;

Fig. 4 is a vertical sectional view; and

Figs. 5 and 6 are sectional views taken on the lines 5--5 and 6-6,respectively, of Fig. 4.

Referring particularly to the drawings, the preferred embodiment of theinvention is applied to a drop-out fuse of the type shown and claimed inmy patent No. 2,074,913, it being understood that it is applicable tomany other types of dropout fuse units, either single or multiple.

Herein, the drop-out fuse assembly is shown as being applied to a crossarm [8 of an ordinary pole type transmission line, although it is to beunderstood that it may be mounted on any supporting structure. In thisinstance, it is supported by a strap metal bracket H depending from thecross arm and having a clamping plate l2 for securing it on one side ofthe cross arm 'by means of bolts I3. The bracket II is here shown asbeing bolted at its lower end to a bracket extension H on one part of atwo piece clamp member I5 which is secured to the middle of a singlebushing type insulator I6 and the insulator is suppo ted at an acuteangle to the verticular, the bra ket extension l4 having an angular seatfor that purpose.

In this instance, the lower end of the insulator carries a pair of fusesupporting arms I! and I8 shaped at their rear ends to embrace oppositesides of the insulator and to be clamped thereon by bolts l9 and 28. Inthe present example, a fuse unit 2| is pivotally carried by the outerends of the arms I! and I8 to be swung into engagement with an uppercontact 22 so that it can drop out initially and then swing downwardly.

For this purpose, the arms have notched hinge bearings 23 and integralguide fingers 24.

As shown in my copending application, Ser. No. 180,423, filed December13, 1937, the fuse unit comprises an ordinary fuse tube having a clamp-5 ing collar 25 secured near its lower end and presenting a pair ofspaced upstanding arms 28 to which are pivoted a pair of arms 21 of ahinge or toggle element 28 shaped at itslower end to straddle the lowerrear portion of the fuse tube. The hinge or toggle element has integraltrunnions 29 Journaled in the bearings 23 and also carries an upstandingterminal 30 having a hook eye 3|. The flexible fuse lead wire 32 istrained around a pivoted cam-shaped guide element 33 on the togglemember 28 extending into the lower end of the fuse tube and the wire issecured under tension to the terminal 38 by a clamping bolt 34.

In the closed position of the fuse the back face of the terminal 38engages a combination contact member and bumper 35 pivoted on a spacerrod or shaft 38 between the arms I! .and I8. This member has-an uppercontact pad or face 31 and a bent lower end 38 and is biased to push outthe fuse unit and also to act as a buffer for the unit after it fallsout. For this purpose, the member has an ear 39 behind the pivot rod orshaft 38 and a tension spring 40 is connected between the clamping bolt20 and the ear. Referring to Fig. 4, the contact member places thespring under tension when the fuse unit is closed. After the fuse unitswings out and strikes the bumper end 38 the member swings clockwise andplaces the spring under tension after the spring passes the dead centerso that the member acts as a buffer to stop the drop-out movement of thefuse unit and the fuse unit will be permitted to hang in a substantiallyvertical position with the hook eye 3| exposed to be engaged by an ordi-4o nary switch hook for removing the unit.

A pair of flexible conductors 4| connect the member 35 to the arms I!and I8 and the arm I8 is shown as having an integral tap lug 42 to whicha line conductor is adapted to be connested in the usual manner.

The upper end of the fuse tube-is shown as having a ferrule 43 carryingthe usual hook eye to enable the fuse unit to be swung to its closedposition by a switch hook. A terminal 44 in the form of a screw plug isconnected to the ferrule and has a ball end cooperating with a socket 45in the contact member 22. In this instance, the contact member is in theform of a flared channel-shaped hood having side flanges 46 which 54serve to guide the fuse terminal into its socket. It has an upwardlycurved wall 41 whichthe ball end of the terminal engages as the fuseunit is swung to its closed position and a rear wall 48 serves to limitthe rearward swinging movement of the fuse unit. A pair of arms 48extend rearwardly from the hood and are pivotally connected by a shaft50 between forwardly projecting arms 51 and 52 on a pair of collarmembers 53 and 54, respectively, bolted to the upper end of the bushinginsulator. The arm Si is shown as having a horizontal ledge 55 at itslower edge to serve as a spacer member between the forwardly projectingarms. The two forwardly projecting arms 5| and 52 also have inwardlyprojecting lugs 56 overhanging the inner ends of the two pivoted arms 49behind the shaft 50 and these arms are connected by an integral web orbar 51 so that the lugs serve as stop shoulders to limit the downwardswinging movement of the upper contact 22.

To exert downward or drop-out pressure on the fuse unit through theterminal and to impart flip-out pressure to the upper end of the tube,there is shown a flip-out finger 58 pivoted on a shaft 59 between twoupstanding ears 60 on the upper wall of the contact member 22 andextending between the rearwardly projecting arms '49. The lower end ofthis finger engages a boss 6| having a fiat face at the rear of theferrule 43. The upper end of the finger above the shaft 59 has an ear 82to which one end of a tension spring 63 is connected and the other endof the spring is secured to the spacer ledge 55 on the arm 5|. Thespring serves not only to exert flipout pressure through the finger onthe upper end of the fuse unit, but also to exert downward pressure onthe upper contact so that good contact is established between the fuseterminal and the contact member. A flexible conductor N is connected toone of the upstanding ears on the contact 22 and also to the ledge 55.The forwardly projecting arm 5| with which the ledge is integral alsohas an upstanding terminal lug 65 to which a line conductor is adaptedto be connected.

Referring to the operation of the fuse assembly,

the fuse tube is adapted to drop out and swing downwardly when the fuseis blown and the lead wire releases the hinge or toggle at the lower endso that the lower contact member can exert pushout pressure on the lowerend. Simultaneously. the upper contact exerts downward pressure and theflip-out finger outward pressure on the upper end so that the fuse unitdrops out rapidly and its upper end cannot fail backward or toward theinsulator. The uppercontact then swings downwardly through an angle ofalfew degrees until it is stopped bv the limiting stop shoulders or lugs55 on the forwardly projecting arms of the collar members. Also. theflip-out finger is limited in its forward movement by striking the rearwall 48 of the upper contact. It will remain in this position until thefuse is replaced and closed. After the fuse falls out and approaches itspendent or vertical position, it strikes the end of the bumper arm'38and swings the bumper arm to a position shown in dotted lines in Fig. 4,in which position the fuse is approximately in a vertical position andthe eye 3| on the terminal member 30 is easily accessible to be engagedby a switch hook for removal of the fuse unit. When the fuse unit isrefused or replaced, it is swung back to, its closed position and theball end of the upper terminal wipes against the curved cam face of thehood shaped contact and raises it to the position shown in Fig. 4, atthe same time pushing the flip-out finger 58 back to its spring biasingposition when the ball snaps into its socket.

From the foregoing description, it will be seen that the improveddrop-out fuse assembly is relatively simple in its construction, rug edin its design and dependable in operation. It has no delicate partswhich require adjustment or replacement. It can be manufactured and soldat a relatively low cost and it has demonstrated its commercialpracticability in connection with electrification projects.

Obviously, the present invention is not restricted to the particularembodiment thereof herein shown and described. Moreover, it is notindispensable that all the features of the invention be used conjointly,since they may be employed advantageously in various combinations andsub-combinations.

What is claimed is:

1. In a. drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a togglelike hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit carried by the insulator and biased to exert drop-out pressureon the unit; and a combined spring biased contact and bumper membercoacting withsaid lower fuse terminal to exert push-out pressure on thefuse unit.

2. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endJ'ournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit carried by the insulator and biased to exert drop-out pressureon the unit; a pivoted spring biased contact member coacting with thelower fuse terminal exerting push-out pressure on the fuse unit; and 2.depending bumper extension on said contact member in the path of thefuse unit to stop it in a substantially vertical hanging position.

3. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit carried by the insulator and biased to exert drop-out pressureon the unit; a spacer rod between said lower arms; and a combinedcontact and bumper member pivoted intermediate its ends on said spacerrod and coacting with the lower fuse terminal and the fuse unit when itdrops out; and a single spring connected to said member to exertpush-out pressure through said siliency to the bumper.

4, In a drop-out fuse assembly of the class II described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit carried by the insulator and biased to exert drop out pressureon the unit; a combined spring biased contact and bumper member coactingwith said lower fuse terminal to exert push-out pressure on the fuseunit; and a spring biased flipout member on the upper contact coactingwith the upper end of the fuse unit to impart initial swinging movementto the unit when the fuse blows.

5. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit carried by the insulator and biased to exert drop out pressureon the unit; a combined spring biased contact and bumper member coactingwith said lower fuse terminal to exert push-out pressure on the fuseunit; a flip-out member on the upper contact coacting with the upper endof the fuse unit to impart initial swinging movement to the unit; and aspring connected to bias both the upper contact and said flip-outmember.

6. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit carried by the insulator and biased to exert drop out pressureon the unit; a combined spring biased contact and bumper member coactingwith said lower fuse terminal to exert push-out pressure on the fuseunit; a flip-out member pivoted on the upper contact acting on the upperend of the fuse unit; and a single tension spring connected to theflip-out member and also exerting drop-out pressure on the uppercontact.

7. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a supporting member connected to the insulator; abearing bracket on the lower end of the insulator; a fuse unit removablyjournaled in said bracket and having a toggle-like hinge at its lowerend; a bracket on the upper end of said insulator; a hood shaped contactmember pivoted on said bracket and having a terminal socket; a ballterminal on said fuse unit adapted to be seated in said socket; a springconnected between said upper bracket and said contact member to exertendwise drop-out pressure on the fuse unit; and means also connected tosaid spring to exert flip-out pressure against the upper end of saidfuse unit.

8. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a supporting member connected to the insulator; abearing bracket on the lower end of the insulater; a fuse unit removablyjournaled in said bracket and having a toggle-like hinge at its lowerend; a bracket on the upper end of said insulator; a hood shaped contactmember pivoted on said bracket and having a terminal socket; a ballterminal on said fuse unit adapted to be seated in said socket; aflip-out finger pivoted on the contact member and coacting with theupper end of the fuse unit; and a spring connected to said finger toimpart flip-out pressure to it and also drop-out pressure to thecontact.

9. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit in the form of a hood having a curved upper guide wall andpivotally carried by the insulator; a spring biasing said contact memberto exert drop-out pressure on the unit; and a combined spring biasedcontact and bumper member coacting with said lower fuse terminal toexert push-out pressure on the fuse unit when the fuse blows.

10. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a toggle-like hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit in the form of a hood having a curved up per guide wall andpivotally carried by the insulator; a spring biasing said contact memberto exert drop-out pressure on the unit; a pivoted spring biased contactmember coacting with the lower fuse terminal exerting push-out pressureon the fuse unit; and a depending, curved bumper extension on thecontact member in the path of the fuse unit to stop it in asubstantially vertical hanging position after it drops out.

11. In a drop-out fuse assembly of the class described, an elongatedupstanding insulator; a pair of spaced rigid arms secured to the lowerend of the insulator and having notched bearings at their forward ends;a fuse unit having a togglelike hinge member near its lower endjournaled in said bearings; a lower fuse terminal on said hinge memberto which the fuse lead is connected; an upper contact member for thefuse unit in the form of a hood having a curved upper guide wall andpivotally carried by the insulator; a spring biasing said contact memberto exert drop-out pressure on the unit; means to limit the downwardswinging movement of said contact member so that the upper fuse terminalwill engage the guide wall upon closing; and a combined spring biasedcontact and bumper member coacting with said lower fuse terminal toexert push-out pressure on the fuse unit when the fuse blows.

- TOMLINSON F. JOHNSON.

